The present invention relates a platelike structural element with outer surfaces of sheet metal plates, such as sheet steel plates, with a foamed material core between the plates, the latter of which is tightly formed to turned surfaces of the plates.
In many construction uses, platelike or slab-like structural elements or panels have been used advantageously, providing they exhibit certain qualities. Various plates of wood or plastic glued shavings, such as chip board or gypsum plaster board, or other slab-like structural elements of organic or inorganic materials have been considered in such construction uses. Such materials cannot always be employed, however, because of their mechanical strength, their combustibility or their low durability to water or dampness.
Structural elements in platelike or slab-like configuration are advantageous where the elements not only have the largest possible area, but are also relatively lightweight and exhibit the necessary mechanical strength, are nonflammable or at least ignite with difficulty, can withstand environmental effects for a long period of time, and exhibit sufficient corrosion resistance.
Such platelike or slab-like structural elements have been usable in building as well as vehicle construction and also in interior furnishings of ships and other vessels.
A problem of the present invention is to produce such a slab-like structural element or panel that has such universal use capability.
This problem is resolved in the structural element incorporating the principles of the present invention wherein at least two sheet steel plates cover the foamed material core and lie next to each other and are seamed together at their edges. Because of this, a platelike or slab-like structural element or panel results of practically any desired length and width. The surfaces of the element of panel are formed of at least two sheet plates positioned next to each other, between which is a foamed material core that is tightly joined to turned surfaces of the sheet steel plates, either in the process of the foaming of the foamed material core between the plates or by gluing or attachment with other suitable adhesives.
The plates preferably are formed of 0.5 mm thick sheet steel, also called body sheet, which can be superficially heat treated and primed.
One such platelike structural element or panel is suitable for the various uses. For most uses such element has adequate strength and a durable, corrosion-resistant surface that is essentially free of joints and seams. A shallow crease only exists in the area of the grooved seam of the two adjacent plates.
Although the sheet metal plates of the present invention could be formed of aluminum having a wide variety of widths, aluminum does have certain disadvantages with respect to its strength and its cost. Thus, sheet steel is preferred for the metal plates of the present invention.
Where the sheet metal to be employed in the element or panel of the present invention is thin, it is frequently only available in narrow widths. The edges of several of such narrow plates could be joined together through a single shear-riveted joint joined by means of grooves. However, the riveted plate edges result in metal which is exposed to the environment which can lead to corrosion. Thus, additional protective measures must be taken with such joints.
In the preferred embodiment of structural element or panel incorporating the principles of the present invention, the plates are joined or seamed at grooves and have the advantage that the cut edge of the plates is imbedded in the groove and is protected by bent back plate layers. The surfaces of both joined plates are thereby contiguous and the groove is sealed externally. In this way, structural elements or panels incorporating the principles of the present invention can be produced in practically in any size, so long as they are still manageable.
Moreover, one or the other plate can also be provided, before the grooving, with a superficial structure or change of form, e.g. with an incorporated slit or crease. The production of the latter form of structural element or panel is preferably continuous, such as from at least two sheet metal coils provided for the upper and lower layers or surfaces. The plate may be continually removed from the coils, transported to corresponding grooving equipment, and seamed together so as to be receptive to a further operation in which the foamed material that forms the core and that joins both sheet metal layers with each other can be positioned between the seamed plates. These structural elements or panels can then be cut to certain desired dimensions and be transported for further processing.
In one principal aspect of the present invention, a platelike structural panel includes first and second surfaces spaced from each other with a core of foamed material therebetween. Each of the surfaces comprises at least a pair of longitudinally extending sheet steel plates each of which has a longitudinal edge extending adjacent the longitudinal edge of the next adjacent plate, and grooved seam means is formed from these edges joining and locking the adjacent plates along their longitudinal edges.
These and other objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description.